Last month, a report by the Environmental Protection Agency inspector general found the U.S. Chemical Safety Board has taken far too long to finish its investigations. Critics say that puts workers and the public in jeopardy. (Read the inspector general's report)

It took Occupational Safety and Health Administration just six months to investigate the explosion at the Horsehead zinc refinery and then fine the company $45,000.

But the Chemical Safety Board -- which recommends safety improvements following industrial accidents -- has still not finished its investigation. The president of the union representing hundreds of Horsehead workers said he had to lobby the safety agency to do its job.

"We put pressure on them, and we also made a call to Sen. (Bob) Casey, who also put the pressure on them for us to get answers so we could get closure, too," said John Jeffers, of US Steelworkers Local 8183.

The workers still do not have closure, and neither do the families of James Taylor and Corey Keller, the workers who died in the explosion.

"We don't have answers for them because we're getting the runaround from our company, and we're also getting no answers from the Chemical Safety Board," Jeffers said.

Horsehead Senior Vice President Ali Alavi said the company has been "quite cooperative" with the safety board, adding, "We sat down with them multiple times."

But in its report, the EPA inspector general blasted the safety board, saying it had a big backlog of open investigations and a high staff turnover rate. Beaver County emergency services director Wesley Hill said that's a concern.

"It's important that we get the results of what happened so we can train, plan and prepare, should that type of incident happen again," Hill said. Jeffers added, "You can't feel safe if you don't have the answers to what happened, how it happened, why it happened."

The Horsehead plant is scheduled to shut down later this year. Up to 800 workers will lose their jobs. Shell has announced tentative plans to build an ethane cracker plant at the site.

TUESDAY UPDATE: The Chemical Safety Board said it has been hit with budget cuts, and a heavier workload because of its investigation into the Deepwater Horizon oil spill in the Gulf of Mexico, all of which forced the Horsehead case to the back burner.

"It obviously was a tragedy for the workers and the families who are involved," managing director Daniel Horowitz said. "There were unsafe conditions at the plant that, frankly, probably should have been looked at years earlier."

Another factor was the company's decision to shut down the Horsehead plant and abandon the manufacturing process that safety investigators called unsafe.